1. Field of the Invention
The present invention relates to an Fe-based amorphous alloy powder applied, for example, to a dust core or a coil-embedded dust core, each of which is used for a transformer, a power supply choke coil, or the like.
2. Description of the Related Art
In concomitance with a recent trend toward a higher frequency and a larger current performance, a dust core and a coil-embedded dust core, which are applied to electronic components, are each required to have excellent direct-current superposing characteristics and a low core loss.
Incidentally, on a dust core having a desired shape formed from an Fe-based amorphous alloy powder with a binding material, in order to reduce a stress strain generated in powder formation of the Fe-based amorphous alloy powder and/or a stress strain generated in molding of the dust core, a heat treatment is performed after the core molding.
Since a heat treatment temperature to be actually applied to a core molded body cannot be set so high in consideration of a heat resistance of a coated wire, a binding material, and/or the like, a glass transition temperature (Tg) of the Fe-based amorphous alloy powder must be set to be low. In addition, a corrosion resistance must also be improved to obtain excellent magnetic characteristics.
As related technical documents, there are U.S. Patent Application Publication No. 2007/0175545, U.S. Pat. No. 7,815,753, Japanese Unexamined Patent Application Publication No. 2009-174034, U.S. Pat. No. 7,132,019, Japanese Unexamined Patent Application Publication Nos. 2009-54615, 2009-293099, and 63-117406, and U.S. Patent Application Publication No. 2007/0258842.